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Maintenance of garter snakes


Garter Snakes are generally easy maintain. I do not intend to be definitiveon the subject of maintenance:- I merely aim to describe those methods that I havefound helpful.

In general, given adequate conditions, garter snakes will thriveand breed.
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My preference is for wooden vivaria with glass doors. This is more foraesthetic than practical reasons. I like to be able to illuminate the cages and observethe snakes. Many other herpetologists prefer to use large plastic containers.

Glassfronted cages have the advantage of allowing better visibility than tubs, are moreeasily stacked, and allow front access which possibly disturbs snakes less. Theyare generally bigger, and if built for the purpose can be made of a suitable sizefor a larger number of garter snakes. They are however more likely to be escapedfrom, and an unexpected birth can result in escaped babies. I have on more than oneoccasion lost small snakes through gaps at the edge of glass doors that I would nothave believed possible. Even with the experience of having had this happen before,I have still made the mistake of thinking "nothing could escape through thattiny gap!" and been proven wrong.

Increasingly I come across evidencethat garter snakes kept in plastic tubs, such as sweater boxes, are less likely tobreed successfully, which may indicate a degree of stress. In general garter snakesare much more active than other commonly kept colubrid snakes, and whilst most ratand king snakes are successfully bred in sweater box containers, garter snakes seemnot to breed so well under these conditions. My own experience has backed this up,and a colleague in California, who is a very successful breeder, tells me that whenhe changed from using sweater boxes to large glass cages, his snakes began to "breedlike rabbits!"

Plastic tubs have the advantages of being easier to maintainand clean, are generally more escape-proof, and are ideal for babies and smallersnakes.

I tend to use a combination of both systems. Larger snakes are keptin wooden cages with glass doors, and juveniles are kept in large plastic tubs.

Thespace required per animal depends on the size of the snake. Most of my cages are48 inches by 24 by 12 (120 cm by 60 by 30). In one such cage I would house perhapssix small snakes (adult males) or three large ones (large females).

garter snake vivariumgarter snake vivarium

click on image to enlarge

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Individual or collective housing?

Again I feel this is a matter for personal preference. I favour smallgroups of snakes kept together, some experts prefer to house individuals alone, andone colleague from Holland keeps about 100 garter snakes together in a large outdoorsenclosure.

Individual housing has the advantage of being better able to monitorsnakes, and recognise problems at an early stage, and in particular identify a poorlyfeeding snake. It enables matings to be better controlled and timed, thus enablingbetter prediction of when babies are due. It reduces the chance of food fights, andaccidental ingestion of other snakes. It reduces the risk of spread of disease.

Grouphousing has the advantage of being more aesthetically pleasing. Garter snakes tendto be rather social animals (in a biological rather than anthropomorphic sense) andon occasions do interact with each other. I frequently find two or more animals kepttogether will hide under the same hide-spot, even though several are available. Irealise this may be due to environmental reasons (e.g. temperature) but do not observethe same phenomenon in my rat snakes or hognose snakes. I have known collectors inthe USA describe finding two garter snakes together in the wild more often than withother colubrids or snakes. I rarely find food-fights a problem, unless worms areused.

It is generally recommended that gravid snakes, particularly close tobirthing time, should be kept alone, to prevent accidental damage to babies (or evencannibalism, which, although rare, has been recorded), and also to reduce stressto the mother, which could result in babies being retained..
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Heating and lighting

The most important issue with heating is that the snakes have a thermalgradient. According to where the snake comes from, time of year, feeding status,gravidity and even time of day, the preferred temperature of the snake varies significantly.I use thermostats connected to a heat mat under the front part of the cage, beneaththe light. The thermostat is set at around 84 deg F. The cooler end of the cage isusually around 70. In particular the more southern species (marcianus, cyrtopsis,sirtalis from Florida) are usually at the hot end, especially when gravid.

Ifthe plastic tub system is favoured, the simple method of heating is to use a heatstrip under one end of the box. This does not really require a thermostat.

Itis important if using heat mats or strips underneath the floor that it covers lessthan half of the cage space. Even low wattage mats can provide a significant heatin confined spaces, and particularly under a hide box. I have measured a temperatureof 112 deg F (48) under a clay hide box over an Ultratherm heat mat. A snake unableto escape from this would quickly die. It is worth bearing in mind that a snake'snatural response to heat is to burrow. If a heat mat is being used underneath a substratein which the snake can burrow, this can result in accidental suicide!

Anotherimportant aspect of temperature is to allow for a drop in temperature at night. Thisis particularly important during pregnancy, as the drop in temperature at night seemsto play a role in initiating parturition. Females kept at a constant warm temperaturecan retain their babies, with catastrophic consequences for both mother and babies.I switch off all heat and lighting at night using a timer switch. Thermostats arenow available that will allow more sophisticated control, but this is probably notnecessary for garter snakes.

Lighting is a controversial issue. Gartersnakes will certainly survive and breed if kept with access only to room light. Thishas the advantage of allowing them to naturally 'key in' to day-length. However,my own experience of using plastic boxes without lights has been that breeding hasoften not been successful. A Californian friend tells me that when he changed fromusing 'sweater boxes' to larger cages with lighting, he suddenly found that the snakes'bred like rabbits' from next to no breeding at all.

I suspect (and have noscientific evidence on which to base this) that some of the more colourful diurnalspecies may benefit from access to UV light, in much the same manner as many colourfullizards do. I now use artificial fluorescent strips, containing UV light, and supposedlysimulating natural daylight. However, these tubes are only replaced when they 'blow',and are at the top of an 12 inch (30 cm) high cage, so the actual UV light receivedby the snakes is likely to be minimal.

I would add that my own observationsshow that T. marcianus in the wild is largely nocturnal, and it may be that no lightis required by this species. They rarely seem to bask in captivity, and indeed someof my animals will only feed at night. Albino animals may also be more at risk frombright UV lights, as their retinas will be poorly protected, and their skin probablymore at risk of damage.
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Cage furnishing

It is important that the snake has access to a secure hide place. I preferto offer two or three so that the snake has a choice of temperature. I use overturnedclay flower pots with a hole cut in the base, and overturned roofing slates. It isimportant to ensure that the drainage hole is covered as snakes can try to get throughand get stuck, with fatal consequences if not detected.

Fresh drinking waterat all times is essential. Snake frequently defecate in their water. I change waterat least twice weekly even if apparently clean. Water bowls should be sturdy anddeep enough not to evaporate quickly.

It is important to be aware that gartersnakes should be kept dry. Although in the wild many live in marshy areas, in thewild they always have access to dry land, and even in marshes and ponds there arealways dry patches in warm weather. A garter snake kept in moist conditions willdevelop skin or respiratory disease.

Some garter snakes like to climb andsturdy branches can be offered.
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Floor substrate

A variety of different substrates are available. Many keepers use newspaperor corrugated card, which is easy to maintain, and inexpensive, although less attractive,and I also find that nervous snakes do not like it, as it does not offer a good gripto the ventral scales, and so makes it hard for the snakes to move quickly.

Inow tend to use either a cat litter based on compressed sawdust, or bark chips. Theseallow for easy 'spot cleaning', and are large enough not to be accidentally swallowed.

Newspaperor any other dry commercial bedding substance would suffice. It is probably importantto avoid sand or particulate matter that might stick to the food and be accidentallyingested, although personally I have never known this cause problems.
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Cages should be cleaned when soiled. Garter snakes fed on fish will defecatefrequently and profusely. They cannot be neglected to the same extent as mouse feeders.I clean my garter snakes twice weekly and my similar sized rosy boas twice monthly!
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Garter snakes as a group tend to be good feeders, and many are ratheromnivorous. Many keepers favour mice, and most garter snakes either readily takemice of suitable size, or can be persuaded to.

Other common prey items areearthworms (if you use these, it is vital to know that they have come from groundin which no pesticides have been used, and to avoid the red-striped "brandlings"from compost heaps, often sold as fishing bait, which are highly acidic and possiblytoxic to snakes), fish, frogs, slugs and even meat.

Keepers should be awarethat there is evidence that some garter snakes are predisposed to thiamine (vitaminB1) deficiency. This is thought to occur if they are fed an exclusive diet of oilyfish, which are rich in an enzyme called thiaminase. This enzyme will destroy thiamine,so even if vitamin supplement is added to the diet or drinking water, it will stillbe destroyed. The manifestations of this deficiency are of loss of co-ordination,head waving, balance disturbance, anorexia, weakness, and finally convulsions anddeath. I have known animals showing the early stages of symptoms to make a full recoverywith a change of diet.

There are herpetologists who do not believe in thephenomenon of dietary-induced thiamine-deficiency in garter snakes. I do believein it, and have had snakes die of these exact symptoms in my early days of snake-keepingin the 1970s, when the easiest (and cheapest!) diet was whitebait, a goldfish-sizedfish sold for the human market. These are eaten whole (by humans and garter snakes!).They are sold frozen in packet of 1 lb (450g). The thiaminase can be destroyed byheating the fish in hot water at 180 deg F (80 deg C) for 5 mins, but this resultsin a very messy product.

Other fish of this thiaminase-containing type includemackerel, spratt and herring.

Another useful food is a product called 'GarterGrub' marketed by Dinosaur Nutrition (a branch of T-Rex). This is sold frozen inpre-packaged containers. It is based on whole vertebrate prey items and is nutritionallycomplete. There are different preparations for adults and juveniles. It is sold inuser-friendly plastic packages from which individual portions can be popped out muchas ice cubes from an ice-tray. Most garter snakes take to it readily. It is availablein Petsmart stores, but in some rural areas or small towns (such as where I live!)it may not be widely available. For a large collection it can work out as an expensivefeeding method:- a 95g container retails at about £4 (US$ 6). Two large female garterscould eat this in one sitting.

Frequency of feeding depends on the food beingoffered, and the size of snake. I generally feed adult snakes once or twice a week,as I use a fish-based diet. I allow the snakes to eat as much as they want. Snakesfed on mice will only require feeding once a week. Babies need more frequent feeds,and for the first two months of life I usually feed them on alternate days. Thisprovides a rapid growth.

Over-eating is rarely a problem in garter snakes,but I have had some animals, usually females, with a tendency to become obese. Theseanimals are restricted to four food items once a week.

One word of warning- hungry snakes will often grab at anything moving when they can smell food. Thiscan sometimes result in accidental bites being sustained, but of more concern isthe risk of snakes accidentally attacking each other. I have seen this many times,and although the snakes usually realise their mistake and let go of the other snake,occasionally the snake will just keep swallowing. This is particularly common inbaby snakes, and especially with worms. If two snakes grab opposite ends of a worm,the faster will sometimes just keep eating, until he has finished the snake attachedto the other end. Invariably this results in the death of both snakes. It is generallya good idea to supervise feeding if snakes are housed collectively.
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Home-made garter snake food

Several years ago I decided to attempt to mass-produce food for my increasinglylarge collection of garter snakes. I decided that I wanted a diet that was reliablyavailable, and based on whole prey animals, and that could be kept frozen. I livenear several trout farms, and have found one that supplies me trout at a good price.

Thetrout are liquidised and mixed with gelatine and vitamin powder and frozen into blocks,of which a strip can be cut off from frozen.

I have used this method of feedingfor three or four years now, and with the exception of my T. cyrtopsis, which aredifficult feeders, all my garter snake have had this exclusive diet for that time.I have encountered no problems that I would consider related to this diet, the onlyunexplained deaths being of some of my albino strain of Florida blue garter snakes,which I consider to be due a genetic defect (see My Collection).Baby Florida blue and Chequered garter snakes have thrived on this diet, and twoanimals have grown to adult size (and have become gravid) in well under a year.

Pleasenote that I am not advocating that other people use this diet. It has not been triedand tested for long enough to fully exclude long-term problems. I attach the detailsof how to make it, but accept no responsibility for problems that may occur as aresult.
  1. Take 4 whole trout of approx. 8 oz each. These must be gutted in advance (as theintestines contain ingredients that prevent the mixture from setting)
  2. Cut the trout into chunks (this makes liquidising easier), or mince it if you haveaccess to a mincer.
  3. Make the gelatine solution. I use gelatine sachets each designed to set 1 pint ofwater. I mix 4 of these (i.e. 1 per trout) in a small amount (about 4 fluid oz) ofvery hot (but not boiling) water until fully dissolved. This is quite tedious andis easier if the container containing the gelatine mixture is placed in a pan ofsimmering water. The less water you can use to mix the gelatine the better. Do notallow the gelatine to boil, and do not let it cool before step 6.
  4. Warm the trout chunks up gently in a microwave so they are slightly warm but notcooked (if they are too cold the gelatine will set too quickly).
  5. Liquidise (blend) the trout chunks for 2 minutes or more to ensure all bones etcare liquidised.
  6. Add the gelatine to the liquidised trout, add 4 teaspoons of vitamin powder and blendfurther.
  7. Spread the paste into a suitable container to form a flat layer. I use the tops ofclear plastic hatchling boxes.
  8. Leave these in a cool place to set, and wrap foil or cling-film around to stop themixture drying out.
  9. Once set it can be removed from the container (it should be a semi-solid strip bynow) and frozen. I find it helps to cut grooves along it before freezing it, andthen you can simply snap off a strip from frozen as required.
  10. When feeding it to snakes, it is easier to cut whilst still frozen, before it goessoft. It is best to put it at the cool end of the cage as it does tend to go softwhen warm.
  11. It does take trial and error to get the mixture of gelatine to trout right. Thesequantities work well for me.

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Cat food
For the last few years I have increasingly used commercial cat food for most of my adult and sub-adult snakes. This appears to have been successful, and most of the snakes have taken readily to it, and have appeared healthy and have bred successfully. I was given this 'tip' by a garter snake enthusiast in Liverpool who has used the food for years. It is worth experimenthing with different brands of food, and the fishier varieties tend to be better tolerated. My present food is Whiskas 'Oh so fishy' which is available from Tescos. In the past I found Asda's 'Tiger seafood selection' better, and to have a higher fish content, but I have no local source for that. For smaller snakes the cat food can be cut into smaller pieces, but I find that most babies do not take readily to it. I therefore feed smaller snakes on strips of my home made food, and during their second year find that most will readily switch to cat food. The main advantage of the cat food is that it is less expensive both financially, but more importantly in terms of time and effort spent making my home made food.


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Hibernation is helpful, if not essential, to the successful breedingof garter snakes. The duration and temperature of hibernation varies according tospecies, and different breeders have their own ideas. It seems that more northerlyspecies will not breed without a prior hibernation, and mating takes effect immediatelyafter hibernation, often within hours. More southerly species may breed without hibernation,and if they are cooled it may be some weeks before mating occurs. I tend to keepmy garters at about 50 to 60 deg F (10 - 15 deg C) for 8 to 12 weeks from early December.Sometimes the snakes know best, and if they go off their food late in the year thenthey are cooled sooner. Most breeders suggest separating males and females duringhibernation, but I can see little need for this, and frequently hibernate animalsin mixed sex groups.

More northern species may require a colder hibernation,and some breeders will hibernate their snakes in a domestic refrigerator.

Priorto hibernation it is important to ensure that the snakes have been starved for twoweeks. This prevents undigested food from decomposing during hibernation.

Afterhibernation there are different ideas about how quickly to warm up the animals. Ihave always followed the perceived wisdom of a gradual increase in temperature over a week or so, and usually find that the animals quickly aim for any hot spots. Oftenthey will refuse food until after their first shed, although some feed almost immediately.Philippe Blais MD, who very successfully breeds Crimson garter snakes in Quebec,warms up his animals with just a 24 hour transition period to normal temperature("Flame Garters - A Variation on an Old Theme" - the Vivarium Vol 9 No6).
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Sexing snakes

Snakes are sexed by one of three methods:-


A,B & C - Female tail; ventral and lateral views. The tail base enlargement noticeablein some females (see B) appear to be male glands, but note that the tail tapers rapidly

D& E - Male tail; ventral and lateral views. Tail base is thick, and this thicknessextends for some distance beyond the vent.

Illustration and description bykind permission of Mr Robert J. Riches, author of 'Breeding Snakes in Captivity',1976

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If you have got everything else right, then this pretty well happenson its own!

Although such a comment may cause offence to some excellent andreputable herpetologists, it is not far from the truth! Both myself and Mr Bob Richeshave experience of Florida blue and Chequered garters breeding repeatedly withoutprior hibernation. Indeed I have had two female juvenile chequered garters have healthylitters at less than 11 months of age, with no prior cooling period. This was accidental,and they mated with their brother with whom they were being housed.

Againthere are varying opinions as to how best to achieve a successful mating. It is certainlyworth introducing the male to the female immediately after hibernation. If that isnot successful, then frequent reintroductions should be tried, particularly aftereither sex has sloughed. My own approach is rather unscientific:- I just leave themtogether and let them get on with it. Those with more voyeuristic tendencies areadvised to avoid this technique as not uncommonly the female(s) become gravid withoutmating having been observed.

Mating is along the usual colubrid line of courtship.Successful mating results in a visible seminal plug or a gaping of the female's cloaca,although I have known successful matings where this was not identifiable.

Itis usually a month or so after mating before pregnancy becomes obvious. A lumpinesscan be felt in the ventral aspect of the female's mid-body. This is best felt whenher muscles are relaxed by letting her gently run through the hands. As the pregnancyprogresses the swelling becomes more pronounced and moves caudally (tailwards!).She often stops feeding in the second half of her pregnancy, after initially eatingvoraciously.

Birth occurs typically 90 to 100 days after mating. The femaleshould be alone, in an escape-proof (for babies!) cage, and there should be plentyof cover for the babies to prevent accidental injury from the mother. Some breedersadvocate a 'nesting box' with damp sphagnum moss inside - this may stimulate themother into giving birth, and also assists the young with their first slough. Theyoung are immediately independent and many start to feed within a day or two. Sloughingcan be from day 1 to day 10.

The babies are cared for in much the same wayas adults. I usually find tiny strips of my home made food are taken readily, butsome require scenting with worms for the first few feeds. One or two stubborn babiesrefuse it for some weeks or months, and despite being fed worms with the same frequency,their growth is significantly less than their siblings.
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